Bitcoin is supposed to allow for “anonymous” transactions, but that doesn’t mean people’s privacy can’t be at risk when dabbling in cryptocurrency markets--as evidenced by fines just issued by South Korea’s data protection regulator.

On Wednesday, the Korea Communications Commission (KCC) whacked eight cryptocurrency exchanges and wallet services with fines ranging from $9,000 to $14,000 for various privacy violations, such as not deleting the data of former customers, and...